You will have to open a return case.
This is the correct advice that you were given in reply to your earlier post.
You may need to send what you did receive back to the seller who must refund you.
Then it will be up to them to try and sort it out with the carrier.
Ebay has not sold you anything or sent you anything. You need to open a return.
Open a return request
To request a return, select the item you want to send back from your recent purchases above, or use the button below. You can also start a return request from your Purchases in My eBay.
Start a return - opens in new window or tab
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)